Card cages are known in the art. In general, a card cage comprises a housing or frame adapted and configured to receive one or more cards (also known as boards or blades). Such cards usually include a main printed wiring board having various electronic components mounted thereon and further usually including a plurality of electrical connectors. These electrical connectors are often disposed proximal a rearward portion of the card and are positioned to mate with corresponding connectors that comprise a part of the card cage (for example, a given card cage will often include a backplane comprising a printed wiring board having circuit traces and connectors to provide for convenient coupling of the circuitry on the cards to other desired locations).
In general, such card cages are designed to comport with certain standard physical and/or electrical standards. For example, the height and depth of the card cage will typically be sized to accommodate a wide variety of cards. In similar fashion, many card cages have a backplane that will cooperate successfully with a variety of different cards as well. As a result, users of such products have a growing familiarity with and expectation that a given card cage will be able to accommodate a variety of different cards. This perception often further includes an expectation that each card slot as provided in a given card cage will be able to accommodate a wide variety (or all) cards regardless of card type or function.
Unfortunately, such is often not the case. In many cases, for good reason, a given card cage and/or a given card slot in a given card cage will not accommodate a given card. In some cases this mismatch comprises a physical mismatch, as where the electrical connectors on a given card do not all align properly with the corresponding connectors in the card cage. In other cases, the mismatch comprises an electrical mismatch, as where the electrical connectors match as between the card and the card cage but the signal-bearing and/or power-bearing paths so created are inappropriate and incorrect. In other cases, both kinds of mismatching can occur. In yet other instances, otherwise physically mismatched connectors are nevertheless still closely enough aligned that, with sufficient physical force being applied, at least some inappropriate connections can be forced.
When such mismatches occur, damage to the card, the card cage, and/or the system as a whole (including other cards in the card cage and/or other devices and components as are connected to or dependent upon the functionality of the card cage and its constituent cards) can result. Such damage may be temporary or permanent, and can include both electrical and physical damage to individual card components and/or the card as a whole.
Warnings and/or instructions regarding proper placement of a given card with respect to a given card cage or card slot can be provided to attempt to ameliorate such problems (for example, such warnings can be displayed on the card cage or on the card and/or can be provided on supplementary materials as are provided with the card or card cage). Unfortunately, such written information is often either ignored and/or unavailable at times of need. It is also difficult, when preparing such warnings and cautions, to anticipate future developments; for example, a given warning may suggest to a user that a particular kind of card should not be placed in a given card slot of a given card cage, when in fact a later-developed card of that particular kind may be properly designed and configured to function successfully in such a setting.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are typically not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.